Re: [Qemu-devel] [PATCH 2/2] raw-posix: Remove O_RDWR when attempting to open a file read-only

[Kevin Wolf]

Avi Kivity schrieb:
> When we open a file, we first attempt to open it read-write, then fall back
> to read-only.  Unfortunately we reuse the flags from the previous attempt,
> so both attempts try to open the file with write permissions, and fail.
> 
> Fix by clearing the O_RDWR flag from the previous attempt.
> 
> Signed-off-by: Avi Kivity <address@hidden>
> ---
>  block/raw-posix.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 5790206..7536a72 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -136,6 +136,7 @@ static int raw_open_common(BlockDriverState *bs, const 
> char *filename,
>      if ((flags & BDRV_O_ACCESS) == BDRV_O_RDWR) {
>          s->open_flags |= O_RDWR;
>      } else {
> +        s->open_flags &= ~O_RDWR;
>          s->open_flags |= O_RDONLY;
>          bs->read_only = 1;
>      }
        
Does the standard say anything about the values of the constants?
Wouldn't it be cleaner to have a s->open_flags &= ~O_ACCMODE before the
if instead, so that O_RDONLY is reset in the other case?

Kevin